I always suspected that my girlfriend contacted my ex-boyfriend behind my back. What should I do?

The key is you. You don't have enough confidence to leave her heart here. If you were kind enough to her and you had this confidence, you wouldn't have this trouble. Besides, you have to accept the fact that she talked about her boyfriend in your heart. If you can't accept it in your heart, even if she has nothing, you will always doubt it. Trust is the most important part of love. Love without trust is naked possession. Everyone belongs only to himself, not to others. I hope you attract her with what you do, not by spying. How empty your love is. Why don't you find someone who really loves you? That's interesting.